1. Field of the Invention
This invention relates to apparatus and a method for successively supplying substantially equal portions of a flowable product from a source thereof to a delivery zone. Specifically, the invention concerns a double piston portioning machine for delivering precise portions of a flowable product such as comminuted meat to a packaging zone. One particular use of the apparatus, for example, is to stuff a product such as sausage in casings where the sausage of an advertised fixed weight is then to be sold at a specific retail price.
2. Description of the Prior Art
In the processing of food items such as sausages and other comminuted meat products, control over the size, shape and weight of the retail product are all of importance. Shape can often be controlled by the way in which the product is delivered to the packaging area. For example, extruders have been employed for some time to deliver the ground meat to a casing which is slipped over the extruder outlet tube or horn. The weight of each individual encased sausage thus becomes primarily a function of the amount of meat delivered to each casing placed over the delivery horn.
Certain retailers, and particularly those that sell high volumes of sausage in casings, often establish a fixed price for a particular size of the sausage. This is especially true as to sausages that are sold as a variety pack retailed at certain seasons of the year as gifts. Similarly, high volume retailers will often offer cased sausages at a fixed price for a designated size, such as three pounds, rather than on an actual per ounce basis. In instances such as these, the meat processor must furnish to its customers a packaged meat product which weighs at least as much as the advertised weight sold at the fixed price. The standard established therefor is a fixed weight as a minimum with all tolerances being on the plus side and therefore to the benefit of the customer. Using the three-pound encased sausage product as an example, the sausage must weight at least three pounds under all circumstances and any variations encountered during processing and packaging must be on the three pounds plus side.
The fixed price product being one that is sold in large volumes, it is also essential that processing machinery be available which will automate the packaging process to the extent possible and minimize direct labor costs.
Previously, processors have determined that they must establish an overage tolerance of at least about 3.5 grams if they are to assure delivery of a three-pound package in all instances. It can therefore be seen that if the overall plus tolerance standard can be reduced to 2.5 grams, the savings to the processor may amount to as much as 30% of the prior unbilled overage.
Meat portioners for delivering a product such as sausage to a casing packaging area have included dual piston machines wherein opposed cylinders have a rod extending therethrough joining respective pistons so that the pistons move in tandem. In this manner, as one piston moves away from the central zone therebetween, the other piston moves toward such zone and vice versa. Thus, delivery of comminuted meat to one cylinder causes the piston therein to move away from the central delivery zone as meat previously supplied to the other cylinder is forced out of its cylinder to the extrusion horn where it may be directed into a sausage casing or the like.
Although the dual piston machine having a central connecting rod for the pistons extending through the cylinders did have some advantages in connection with portioning of the meat into individual segments of essentially the same size, the construction of the machines was such that cleaning of the components was very difficult, the portioning accuracy was compromised by the nature of the machine construction, and product throughput was somewhat limited by the mechanical arrangement employed.